<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <div></div>
  <div></div>
  <div></div>
  <script>
    //1 数组合并
    const arr1 = [123,234,345]
    const arr2 = [456,567,678]
    // const arr = arr1.concat(arr2)
    const arr = [...arr1,...arr2]
    console.log(arr)

    //2 数组克隆
    const arr3 = [1,2,3]
    const arr4 = [...arr3]
    console.log(arr4)

    //3 伪数组转换为真数组
    const divs = document.querySelectorAll('div')
    const divArr = [...divs]
    console.log(divArr)

  </script>
</body>
</html>